<?php
    // +----------------------------------------------------------------------
    // | ThinkPHP [ WE CAN DO IT JUST THINK ]
    // +----------------------------------------------------------------------
    // | Copyright (c) 2006~2017 http://thinkphp.cn All rights reserved.
    // +----------------------------------------------------------------------
    // | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
    // +----------------------------------------------------------------------
    // | Author: liu21st <liu21st@gmail.com>
    // +----------------------------------------------------------------------
    namespace think;

    use think\exception\ClassNotFoundException;

    class Session {
        protected static $prefix = '';
        protected static $init   = null;

        /**
         * 设置或者获取session作用域（前缀）
         * @param string $prefix
         * @return string|void
         */
        public static function prefix($prefix = '') {
            if (empty($prefix) && null !== $prefix) {
                return self::$prefix;
            } else {
                self::$prefix = $prefix;
            }
        }

        /**
         * session获取并删除
         * @param string      $name   session名称
         * @param string|null $prefix 作用域（前缀）
         * @return mixed
         */
        public static function pull($name, $prefix = null) {
            $result = self::get($name, $prefix);
            if ($result) {
                self::delete($name, $prefix);
                return $result;
            } else {
                return;
            }
        }

        /**
         * session获取
         * @param string      $name   session名称
         * @param string|null $prefix 作用域（前缀）
         * @return mixed
         */
        public static function get($name = '', $prefix = null) {
            empty(self::$init) && self::boot();
            $prefix = !is_null($prefix) ? $prefix : self::$prefix;
            if ('' == $name) {
                // 获取全部的session
                $value = $prefix ? (!empty($_SESSION[$prefix]) ? $_SESSION[$prefix] : []) : $_SESSION;
            } elseif ($prefix) {
                // 获取session
                if (strpos($name, '.')) {
                    list($name1, $name2) = explode('.', $name);
                    $value = isset($_SESSION[$prefix][$name1][$name2]) ? $_SESSION[$prefix][$name1][$name2] : null;
                } else {
                    $value = isset($_SESSION[$prefix][$name]) ? $_SESSION[$prefix][$name] : null;
                }
            } else {
                if (strpos($name, '.')) {
                    list($name1, $name2) = explode('.', $name);
                    $value = isset($_SESSION[$name1][$name2]) ? $_SESSION[$name1][$name2] : null;
                } else {
                    $value = isset($_SESSION[$name]) ? $_SESSION[$name] : null;
                }
            }
            return $value;
        }

        /**
         * session自动启动或者初始化
         * @return void
         */
        public static function boot() {
            if (is_null(self::$init)) {
                self::init();
            } elseif (false === self::$init) {
                if (PHP_SESSION_ACTIVE != session_status()) {
                    session_start();
                }
                self::$init = true;
            }
        }

        /**
         * session初始化
         * @param array $config
         * @return void
         * @throws \think\Exception
         */
        public static function init(array $config = []) {
            if (empty($config)) {
                $config = Config::get('session');
            }
            // 记录初始化信息
            App::$debug && Log::record('[ SESSION ] INIT ' . var_export($config, true), 'info');
            $isDoStart = false;
            if (isset($config['use_trans_sid'])) {
                ini_set('session.use_trans_sid', $config['use_trans_sid'] ? 1 : 0);
            }
            // 启动session
            if (!empty($config['auto_start']) && PHP_SESSION_ACTIVE != session_status()) {
                ini_set('session.auto_start', 0);
                $isDoStart = true;
            }
            if (isset($config['prefix']) && (self::$prefix === '' || self::$prefix === null)) {
                self::$prefix = $config['prefix'];
            }
            if (isset($config['var_session_id']) && isset($_REQUEST[$config['var_session_id']])) {
                session_id($_REQUEST[$config['var_session_id']]);
            } elseif (isset($config['id']) && !empty($config['id'])) {
                session_id($config['id']);
            }
            if (isset($config['name'])) {
                session_name($config['name']);
            }
            if (isset($config['path'])) {
                session_save_path($config['path']);
            }
            if (isset($config['domain'])) {
                ini_set('session.cookie_domain', $config['domain']);
            }
            if (isset($config['expire'])) {
                ini_set('session.gc_maxlifetime', $config['expire']);
                ini_set('session.cookie_lifetime', $config['expire']);
            }
            if (isset($config['secure'])) {
                ini_set('session.cookie_secure', $config['secure']);
            }
            if (isset($config['httponly'])) {
                ini_set('session.cookie_httponly', $config['httponly']);
            }
            if (isset($config['use_cookies'])) {
                ini_set('session.use_cookies', $config['use_cookies'] ? 1 : 0);
            }
            if (isset($config['cache_limiter'])) {
                session_cache_limiter($config['cache_limiter']);
            }
            if (isset($config['cache_expire'])) {
                session_cache_expire($config['cache_expire']);
            }
            if (!empty($config['type'])) {
                // 读取session驱动
                $class = false !== strpos($config['type'], '\\') ? $config['type'] : '\\think\\session\\driver\\' . ucwords($config['type']);
                // 检查驱动类
                if (!class_exists($class) || !session_set_save_handler(new $class($config))) {
                    throw new ClassNotFoundException('error session handler:' . $class, $class);
                }
            }
            if ($isDoStart) {
                session_start();
                self::$init = true;
            } else {
                self::$init = false;
            }
        }

        /**
         * 删除session数据
         * @param string|array $name   session名称
         * @param string|null  $prefix 作用域（前缀）
         * @return void
         */
        public static function delete($name, $prefix = null) {
            empty(self::$init) && self::boot();
            $prefix = !is_null($prefix) ? $prefix : self::$prefix;
            if (is_array($name)) {
                foreach ($name as $key) {
                    self::delete($key, $prefix);
                }
            } elseif (strpos($name, '.')) {
                list($name1, $name2) = explode('.', $name);
                if ($prefix) {
                    unset($_SESSION[$prefix][$name1][$name2]);
                } else {
                    unset($_SESSION[$name1][$name2]);
                }
            } else {
                if ($prefix) {
                    unset($_SESSION[$prefix][$name]);
                } else {
                    unset($_SESSION[$name]);
                }
            }
        }

        /**
         * session设置 下一次请求有效
         * @param string      $name   session名称
         * @param mixed       $value  session值
         * @param string|null $prefix 作用域（前缀）
         * @return void
         */
        public static function flash($name, $value) {
            self::set($name, $value);
            if (!self::has('__flash__.__time__')) {
                self::set('__flash__.__time__', $_SERVER['REQUEST_TIME_FLOAT']);
            }
            self::push('__flash__', $name);
        }

        /**
         * session设置
         * @param string      $name   session名称
         * @param mixed       $value  session值
         * @param string|null $prefix 作用域（前缀）
         * @return void
         */
        public static function set($name, $value = '', $prefix = null) {
            empty(self::$init) && self::boot();
            $prefix = !is_null($prefix) ? $prefix : self::$prefix;
            if (strpos($name, '.')) {
                // 二维数组赋值
                list($name1, $name2) = explode('.', $name);
                if ($prefix) {
                    $_SESSION[$prefix][$name1][$name2] = $value;
                } else {
                    $_SESSION[$name1][$name2] = $value;
                }
            } elseif ($prefix) {
                $_SESSION[$prefix][$name] = $value;
            } else {
                $_SESSION[$name] = $value;
            }
        }

        /**
         * 判断session数据
         * @param string      $name session名称
         * @param string|null $prefix
         * @return bool
         */
        public static function has($name, $prefix = null) {
            empty(self::$init) && self::boot();
            $prefix = !is_null($prefix) ? $prefix : self::$prefix;
            if (strpos($name, '.')) {
                // 支持数组
                list($name1, $name2) = explode('.', $name);
                return $prefix ? isset($_SESSION[$prefix][$name1][$name2]) : isset($_SESSION[$name1][$name2]);
            } else {
                return $prefix ? isset($_SESSION[$prefix][$name]) : isset($_SESSION[$name]);
            }
        }

        /**
         * 添加数据到一个session数组
         * @param  string $key
         * @param  mixed  $value
         * @return void
         */
        public static function push($key, $value) {
            $array = self::get($key);
            if (is_null($array)) {
                $array = [];
            }
            $array[] = $value;
            self::set($key, $array);
        }

        /**
         * 清空当前请求的session数据
         * @return void
         */
        public static function flush() {
            if (self::$init) {
                $item = self::get('__flash__');
                if (!empty($item)) {
                    $time = $item['__time__'];
                    if ($_SERVER['REQUEST_TIME_FLOAT'] > $time) {
                        unset($item['__time__']);
                        self::delete($item);
                        self::set('__flash__', []);
                    }
                }
            }
        }

        /**
         * 清空session数据
         * @param string|null $prefix 作用域（前缀）
         * @return void
         */
        public static function clear($prefix = null) {
            empty(self::$init) && self::boot();
            $prefix = !is_null($prefix) ? $prefix : self::$prefix;
            if ($prefix) {
                unset($_SESSION[$prefix]);
            } else {
                $_SESSION = [];
            }
        }

        /**
         * 启动session
         * @return void
         */
        public static function start() {
            session_start();
            self::$init = true;
        }

        /**
         * 销毁session
         * @return void
         */
        public static function destroy() {
            if (!empty($_SESSION)) {
                $_SESSION = [];
            }
            session_unset();
            session_destroy();
            self::$init = null;
        }

        /**
         * 暂停session
         * @return void
         */
        public static function pause() {
            // 暂停session
            session_write_close();
            self::$init = false;
        }

        /**
         * 重新生成session_id
         * @param bool $delete 是否删除关联会话文件
         * @return void
         */
        private static function regenerate($delete = false) {
            session_regenerate_id($delete);
        }
    }
